Hi Francisco,
I see you want to simulate a planet orbiting a star using MATLAB graphics and want to make the plot realistic in 3D by simulating a star emitting light and the planets reflecting the light.
I also understand that you want to be able to select objects that are affected by the light. You can simulate the required behaviour by multiple axes.
I see you want the star to not get affected by light source that is positioned at the center of it. To achieve this, you can stack two axes on top of another. You can place the light source and planet in one axis and the star in another axis. Because light sources only affect the objects in it's axis, the star which is in the other axis will not be affected. You can modify the above code something like below:
[X,Y,Z] = sphere();
X2 = X + 4;
Y2 = Y + 4;
Z2 = Z;
max_limit = 5;
figure; %initialize a figure
surf(X,Y,Z, 'FaceColor', "y" , 'EdgeAlpha', 0);
material dull;
daspect([1 1 1]);
xlim([-5 5]);
ylim([-5 5]);
zlim([-5 5]);
axis_star = gca;
%create another axis and place it in the same position as the other axis
axis_planet = axes('position', get(axis_star, 'position'));
surf(X2,Y2,Z2, 'FaceColor', "b" , 'EdgeAlpha', 0)
material dull;
daspect([1 1 1]);
light("Position", [0 0 0], "Style", "local", "Color", "w");
lighting gouraud;
xlim([-5 5]);
ylim([-5 5]);
zlim([-5 5]);
xlabel("X");
ylabel("Y");
zlabel("Z");
title("Plot of the planet");
%make the top axis transparent
set(axis_planet, 'color', 'none');
Hope this Helps!
